Spatio-temporal variations of surface creep along the Hazar-Palu Segment of the East Anatolian Fault, Turkey

Aseismic creep is detected and started to be monitored along the 100 km-long Palu-Hazar Segment of the Eastern Anatolian Fault (EAF) in Turkey, a major plate boundary between Anatolia and Arabia. We used creepmeters, InSAR, GPS, and seismic observations to document the extent and magnitude of this motion in order to increase our knowledge on the spatiotemporal variation of creep along the EAF, its relationship with the lithology and tectonic structures, and the stress change on the neighboring fault segments. Until now, we observed the region with continuous GPS and survey GPS measurements with near (~ 0.1- 4 km to the fault) and far-field (~25 – 225 km from the fault) stations to determine the depth of the creep zone and its velocity along the EAF. We processed 6 years (2014 – 2019) of continuous and 7 campaign (2015 – 2019) GPS data with GAMIT/GLOBK software. With elastic models, we determined a creep rate that reaches about 5 ± 0.3 mm/yr from GPS observations (50% of secular velocity). In addition to surface control of the creeping zone, we analyzed the deformations, by using three Terrestrial Laser Scanner (TLS) survey, in the Palu railway tunnel that crosses the fault where the walls of the tunnel have been offset by 15 ± 2 mm since the construction in the middle of the last century. Also, two creepmeters were installed inside the tunnel and transient creep anomalies are detected. These results are correlated with seismic and InSAR data (This study is supported by TUBITAK 1001 projects 114Y250 and 118Y450).

Keywords: Hazar-Palu, Creep, East Anatolian Fault, Earthquake, GPS, InSAR, TLS